Drill bit

ABSTRACT

A double ended drill bit having two sets of cones mounted back to back in a cone holder with means for rotating the cone holder about a horizontal axis to expose the second bit for drilling after the teeth on the cones on the first have become worn. Such apparatus includes means for moving the drill bit assembly out of a housing and rotating the drill bit assemblies so as to expose the unworn bit for use in drilling the well.

United States Patent 1191 1111 3,847,236

Coalson 1 Nov. 12, 1974 [54] DRILL BIT $133,564 10/1938 Patton 175/258 X2590,0531 3/1952 Taylor 175/383 [76] lnvemor- John coals, 10502 valley3.066.749 12/1962 Hildebrandt 175/383 x 5%?51519:L83JJi BEQI11IEK1 3,369618 2/1968 MOON? 175/258 x [22] Filed: June 28, 1973 PrimaryExaminer-David H. Brown pp NO 374 522 Attorney, Agent, or Firm-Pravel &Wilson [57] ABSTRACT 17558352111552; A double ended drill bit having twosets of Cones [58] Field 331 263 mounted back to back in a cone holderwith means for 267 5 rotating the cone holder about a horizontal axis toexpose the second bit for drilling after the teeth on the cones on thefirst have become worn. Such apparatus [56] References Cited includesmeans for moving the drill bit assembly out of UNITED STATES PATENTS ahousing and rotating the drill bit assemblies so as to 1 gudley 175/383expose the unworn bit for use in drilling the well.

1 ortinas 175/383 X 1,716,741 6/1929 Schwalel 175/383 7 Clalms, 6 DrawmgFlgures PAIENTEUNBY12 mm 1184? 236 SHEEI 10$ 3 PAIENTEUNOY 12 19743.847236 SHE 2 BF 3 PAIENIEBNUV 12 mm $847,236

sum 30? 3 DRILL BIT BACKGROUND OF THE INVENTION 1. Field of theInvention The present invention relates to oil well drilling bits andspecifically to a drill bit including a double ended bit assembly withmeans for rotating the bit assembly after the first bit has become wornso as to expose the unworn teeth of the second bit for drilling.

2. Brief Description of the Prior Art In drilling oil and gas wells andthe like, particularly as the drilling progresses into depths which areseveral thousand feet beneath the surface, it becomes important toobtain the maximum safe and efficient wear on a drill bit prior towithdrawing the bit from the well bore and replacing it with a new bitdue primarily to the time and expense of making a trip to replace thebit. If the bit is run after the teeth are worn out, little effectivedrilling is accomplished; after a bearing is worn out, a cone may bedropped in the hole thereby necessitating a fishing job which is timeconsuming and expensive. If the drill bit is withdrawn from the wellbefore it has been completely worn out, then there is a waste of theunused portion of that bit as it is not feasible to return a worn bit inthe hole due to the time and expense of withdrawing it. It is thereforethe object of the present invention to provide a new and improved doubleended drill bit which includes first and second bits mounted back toback on a single carrier with means for rotating the carrier so as toexpose the unworn portion of the bit after the first portion has becomeworn. With the apparatus of this invention the trip time may besubstantially reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded isometric viewof the drill bit of the present invention with the bits extended beneaththe housing;

FIG. 2 is a vertical sectional view of the drill bit apparatus with thebits in a retracted position;

FIG. 3 is a vertical sectional view showing the drill bits in theextended position and rotated ninety degrees from the position shown inFIG. 2;

FIG. 4 is a side elevation partially in sections taken on line 4-4 ofFIG. 3 showing the drill bits in the extended positions and rotatedninety degrees from the position shown in FIG. 2;

FIG. 5 is an enlarged view showing the details of the rotating apparatusfor rotating the drill bit carriage horizontally and;

FIG. 6 is a sectional view taken on line 66 of FIG. 2 showing additionaldetails of the apparatus for rotating the drill bit carrier.

DESCRIPTION OF THE PREFERRED EMBODIMENT The apparatus of the presentinvention is designated generally B in FIG. 1 of the drawings. Suchapparatus includes a bit housing H, a drill bit carriage C on which anupper bit assembly U and a lower bit assembly L are mounted. Thecarriage C is pivotally mounted between a pair of depending arms forminga part of a yoke mechanism Y which will be described in detailhereinafter. With this apparatus, the drill bit is inserted into thewell bore and used for drilling until the teeth on the lower coneassembly L become worn. Thereafter, the

yoke Y is pumped downwardly from a retracted position shown in FIG. 2 toan extended position shown in FIG. 1 and the carriage C is then rotatedto expose the upper cone assembly U to the face of the bottom of thewell bore for continued drilling. Thus, it will be appreciated, thatwith the apparatus of the present invention a worn drill bit may bereplaced with a new unworn drill bit without requiring a trip to thesurface for replacing the worn bit.

Considering now the apparatus of the present invention in more detail,the housing H shown in FIGS. 1 and 2 of the drawings comprises a hollowtubular member 11 having an inwardly and upwardly inclined annularshoulder 12 which swedges the hollow tubular portion 11 up to a smallerdiameter hollow neck portion 13 which is threadedly connected to thedrill collar or other member at the lower end of the drill string (notshown). A hollow tubular member 11 has a bore 15 extending axiallythereof with a counter bore 16 formed in the neck portion 13 throughwhich drilling fluid is circulated as will be described hereinafter. Apiston member 20 is disposed in the bore 15 and is slidably mountedtherein. As shown, an annular shoulder 22 is provided in the bore 15 forreceiving the lower end of a. coil spring member 24. The upper end ofthe coil spring engages an annular shoulder 26 formed on the upper endof the piston 20 for urging such piston member upwardly in the bore 15.As shown, an O-ring seal 28 is provided in the lower annular shoulder 22for engaging the outer surface 20 of the piston 20 and an annular seal29 is provided in the upper annular shoulder 26 for engaging the innersurface of the bore 15.

The piston member 20 includes a hollow cavity or chamber 28 formedtherein which is of substantially the same diameter as the counter bore16 in the next portion 13. Such chamber is preferably formed axially ofthe piston 20 and provides an upper circumferentially extending inclinedannular shoulder 30.

The chamber 28 in the piston 20 is formed with a conical bottom 32 whichhas a passage 33 extending thereto for receiving a fluid conductor pipe35 which is mounted on a webbed member or flange 37 formed in the bottomof the housing 11. As best seen in FIGS. 2 and 3 of the drawings, thetubular conductor pipe 35 projects upwardly from the webbed member 37through the opening 33 into the chamber 28 in the piston 20 and alsodownwardly through the drill bit carriage C as will be described indetail hereinafter. The tubular member 35 is provided with a passage oropening 38 which extends therethrough for conducting drilling fluid fromthe chamber 28 on to the face of the cones of the drill bit as will bedescribed hereinafter.

An O-ring seal or other suitable type of sliding seal 40 is provided inthe opening 33 for sealingly engaging the outer surface of the tubularconduit to 35.

The lower end of the piston 20 includes a pair of oppositely disposeddownwardly projecting arms 42 which comprise the forks of the yoke Y.Such arms 42 project downwardly from the piston 20 and are provided forrotatably mounting the carriage C therein. As shown in FIGS. 1 and 2 ofthe drawings, the yoke or arms 42 have suitable openings 44 therein forreceiving the bolts or other threaded member 46 which pivotally mountthe carriage C between the opposed yoke arms 44. Also, the lower ends 43of the arms 42 are tapered or inclined inwardly and are preferablyprovided with hard surface cutting material or teeth 43'.

Also, as shown in the drawings there are three arched cavities providedin the lower end of the housing H for receiving the three cones of theupper bit U when such bit is in the retracted position shown in FIG. 2of the drawings. The three arched cavities are formed by thecircumferentially spaced downwardly projecting members 47, 48 and 49.Curved or arched surfaces 47', 48 and 49 are formed between theprojections and are curved to fit the radius 80' of the cones 80, 81 and82. Such curved or arched surfaces engage the cones when in theretracted position in the housing H and transfer torque from the housingH to the cone carrier C for turning the cones on the opposite side ofthe disc C when drilling.

Further, the downwardly projecting members 47, 48

and 49 preferably have tapered tips which are insertable into suitableopenings 47" in the carrier disc 60 to further transfer torque from thehousing H to the drill cones. Also, as shown in FIGS. 2 and 3 of thedrawings the upper cylindrical or tubular portion 11 of the housing H isprovided with a pair of slots or notches 50 for receiving the arms 42 ofthe piston 20. As shown, the upper ends of the arms 42 are provided withradially extending shoulders 43 and the upper end of the notch or groove50 is provided with a corresponding radially extending shoulder 52 forproviding a stop for the piston yoke Y when the piston is in theretracted position shown in FIG. 2.

The bit carriage C preferably comprises a disc shaped member 60 which ispivotally mounted between the arms 42 of the yoke Y. Such disc C hassuitable threaded openings 61 on opposite sides thereof for receivingthe threaded connecting bolts 46 which extend through opening 44 andarms 42. A central opening 64 is provided in the disc member 60 forreceiving the lower end of the fluid conduit tube 35. Such centralopening 64 is preferably a tapered opening having a larger diameter atits outer end 64 than it has at its midpoint 66 so as to provide atapered or conical guide for guiding the lower end of the fluid conduit35 therein.

The disc shaped carriage C also includes three circumferentially spacedcone blocks 70, 71 and 72 for carrying the three upper cones 80, 81 and82 respectively. Similarly, blocks 90, 91 and 92 are formed on theopposite side of the disc on each of the blocks 70, 71 and 72 forsupporting the lower cones 93, 94 and 95, respectively.

As best seen in FIG. 2 of the drawings, the blocks 70 and 90 areprovided with outer arcuate surfaces 74 and 94 and are also providedwith inclined inner surfaces 75 and 9S. Suitable cone mounting pins 76and 96 are provided for carrying the bearings 77 and 97 on which thecones 80 and 93, respectively, are rotatably mounted. Such cones 80 and93 are provided with circumferentially extending rows of suitableabrasive members or teeth 79 and 99, respectively. It will beappreciated that each of the cones in the upper cone section U and thelower cone section L are substantially identical as are the cone supportblocks 70, 90, 71, 91 and the like' and that the bearing supportassembly for each of the cones is also substantially identical.

Each of the circumferentially spaced cone blocks 70, 71 and 72 and thelower blocks 90, 91, and 92 are provided with a pair of substantiallyparallel sides 70, 71' and the like. The parallel sides 50' of the slots50 in the housing H engage the adjacent parallel sides 42' of the arms42 when the arms are retracted into such housing to provide a means fortransmitting rotation from the housing to the cone carriage C.

As best seen in FIGS. 5 and 6 of the drawings, a

spring motor actuated rotating drive means is provided for rotating thecarriage C about the axis extending between the mounting bolt 46. Aguide pin shown in FIG. 1 as well as FIGS. 5 and 6 projectslaterallyfrom the outer surface of the cone block 70. Such pin is received in asemi-circular or arcuate groove 112 formed on the inner surface 42" ofthe arm 42 for receiving the guide pin 110. Such arcuate groove 112 isconcentric with the opening 44 through which the mounting pin 46extends. A spring motor 115 encircles the pin 46 and has its inner end116 positioned in a suitable opening 117 in the block 70 and itsopposite end 119 disposed in a suitable radially extending opening 120in the arm 42. Thus, a means is provided for rotating the carriage C formoving the upper cones 80, 81 and 82 into a lower position as will bedescribed in detail herein. It will be appreciated that the carriage canbe rotated by hydraulic or other means, if desired.

In using the apparatus of the present invention the bit housing H isthreaded or otherwise secured to the lower end of the drill string andlowered into a well bore for drilling oil or gas wells or the like. Inthe drilling position as illustrated in FIG. 2 of the drawings thepiston 20 is retracted into the bore 15 with the shoulders 43 at theupper end of the yoke arms 42 adjacent the top shoulder 52 of the slots'50. Drilling fluid is circulated through the bore 16, the passage 28and the piston 20 and through the fluid conduit tube 35 and directedoutwardly through the inclined ports 35' which directs the fluid on toeach of the three cones forming the lower bit L. During drilling in thisposition, the rotation or torque imposed on the housing 11 istransferred to'the yoke arms 42 and through the pins 46 to the carriageC and thence to the bit L.

After the bit L has become worn, the carriage C is rotated so as toexpose the upper bit U to the bottom of the port hole so as to provide anew bit for continued drilling without the necessity of making a trip toreplace a worn bit.

In order to rotate the carriage C a bit housing H in the bore hole 200is raised so as to provide a space above the bottom 210 in which torotate the carriage. Thereafter, fluid pressure on the drilling fluid inthe counter bore 16 and chamber 28 are increased and such fluid pressureacts on the upper shoulder 30 of the piston 20 and also on the inclinedbottom portion 32 to move the piston 20 downwardly relative to thehousing 11 as shown in FIGS. 2, 3 and 4 of the drawings. The piston 20moving downwardly carries with it the arms 42 and the assembly is moveddownwardly so as to allow the bits U and L to clear the lower end of thehousing H when rotated one hundred eighty degrees so as to present theupper bit U for continued drilling on the bottom of the bore hole 210.

The foregoing disclosure and description of the invention areillustrative and explanatory thereof, and various changes in the size,shape, and materials as well as in the details of the illustratedconstruction may be made without departing from the spirit of theinvention.

What is claimed is:

1. A drill bit comprising:

a housing adapted to be connected to a drill string,

a bit carriage mounted in said housing and having conical drill bitsmounted on opposite sides thereof,

means for moving said carriage out of said housing,

and

means for rotating said carriage relative to said housing whereby theconical drill bits on either side of said carriage may be exposed fordrilling.

2. The invention of claim 1, including:

bias means for urging said bit carriage inwardly relative to saidhousing.

3. The invention of claim 1, including:

means in said housing for limiting axial movement of said bit carriagemeans relative to said housing.

4. The invention of claim 1 wherein:

said means for moving said drill bit carriage comprise yoke meansmovable axially relative to said housing and wherein said drill bitcarriage is rotatably mounted in said yoke means.

5. The invention of claim 4, wherein:

said housing comprises a hollow member having a longitudinally extendingshoulder for engaging said yoke means to rotate said yoke with saidhousing to drive said drill bit mounted in said yoke.

6. The invention of claim 1, wherein:

said means for rotating said bit carriage includes spring means.

7. The invention of claim 6, wherein:

said spring means comprise coil spring motor means connecting said yokeand bit carriage.

1. A drill bit comprising: a housing adapted to be connected to a drillstring, a bit carriage mounted in said housing and having conical drillbits mounted on opposite sides thereof, means for moving said carriageout of said housing, and means for rotating said carriage relative tosaid housing whereby the conical drill bits on either side of saidcarriage may be exposed for drilling.
 2. The invention of claim 1,including: bias means for urging said bit carriage inwardly relative tosaid housing.
 3. The invention of claim 1, including: means in saidhousing for limiting axial movement of said bit carriage means relativeto said housing.
 4. The invention of claim 1 wherein: said means formoving said drill bit carriage comprise yoke means movable axiallyrelative to said housing and wherein said drill bit carriage isrotatably mounted in said yoke means.
 5. The invention of claim 4,wherein: said housing comprises a hollow member having a longitudinallyextending shoulder for engaging said yoke means to rotate said yoke withsaid housing to drive said drill bit mounted in said yoke.
 6. Theinvention of claim 1, wherein: said means for rotating said bit carriageincludes spring means.
 7. The invention of claim 6, wherein: said springmeans comprise coil spring mOtor means connecting said yoke and bitcarriage.